Electrical machine with permanent magnet excitation - has polygonal stator yoke supporting permanent magnets and preventing their demagnetisation

摘要

The rotating machine has a permanently magnetic stator and a wound rotor. The air-gap (8) between rotor (1) and the permanent magnets (5) increases from the centre towards the neutral zones (9) between adjacent magnets. The magnets are supported on the inside of a polygonal frame (4) that acts as magnetic return or yoke. The number of corners to the polygon is equal to the number of poles to the machine. The magnets are plate shaped and extend into the corners of the polygon.